Effect of heat treatment on microstructures and properties of Zr-rich α TiZrAl alloy
The microstructures and properties of two kinds of zirconium-enriched α alloys (Ti60Zr40)97Al3 (mass fraction/％,the same below) and (Ti50Zr50)97Al3 via different heat treatments were investigated and analyzed based on optical microscope (OM) observation,differential scanning calorimetric (DSC) measurement,X-ray diffraction (XRD) measurement,scanning electron microscope (SEM) observation and tensile tests at room temperature.The results show that after 850 ℃/40 min annealing,microstructures consisting of basket-weave α phase and a small amount of reticular β phase are formed in the alloys. After 850 ℃/40 min quenching,the acicular α' martensite phase is formed. After 850 ℃/40 min quenching and then 600 ℃/4 h aging,a large part of α' martensite phase converts into α phase,and the microstructures of the alloys consist of α and α'remain phases. The yield strength of the T40Z3A alloy can reach 1100 MPa,with a favourable tensile elongation of 7％. The T50Z3A alloy exhibits higher strength but lower ductility than those of the T50Z3A alloy. Due to the higher content of Zr element,the T50Z3A alloy has more reticular β phase after annealing and more remaining α' martensite phase after quenching and aging,which results in higher strength and lower ductility.
Ti-Zr alloyannealingquenching and agingphase transformationmicrostructuremechanical property
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